Transmission power control method and apparatus for mobile communication system

ABSTRACT

A transmission power control apparatus is adapted to control a reference value for controlling a transmission power of a mobile terminal equipment based on a reception quality of a plurality of radio access bearers at a base station apparatus, with respect to a physical channel to which the plurality of radio access bearers are mapped, when making a radio connection between the mobile terminal equipment and the base station apparatus in a mobile communication system. The transmission power control apparatus includes a judging part configured to judge whether or not a radio access bearer that is a monitoring target of the reception quality is an audio transmission radio access bearer in a silent state, based on multiplexed information; and a switching part configured to switch the radio access bearer that is the monitoring target of the reception quality to a radio access bearer other than the audio transmission radio access bearer in the silent state, if the judging part judges that the radio access bearer that is the monitoring target of the reception quality is the audio transmission radio access bearer in the silent state. The reference value for controlling the transmission power of the mobile terminal equipment is controlled based on a reception quality of the radio access bearer other than the audio transmission radio access bearer in the silent state.

BACKGROUND OF THE INVENTION

This application claims the benefit of a Japanese Patent Application No.2003-359250 filed Oct. 20, 2003, in the Japanese Patent Office, thedisclosure of which is hereby incorporated by reference.

1. Field of the Invention

The present invention generally relates to transmission power controlmethods and apparatuses for mobile communication systems, and moreparticularly to a transmission power control method and an apparatus forcontrolling a transmission power of a mobile terminal equipment (UE)based on a wave reception quality at a base station apparatus (Node-B)when making a radio connection between the mobile terminal equipment(UE) and the base station apparatus (Node-B) in a mobile communicationsystem employing Code Division Multiple Access (CDMA).

2. Description of the Related Art

A description will be given of an up-link transmission power controlbased on Signal-power-to-Interference-power Ratio (SIR) in CDMA, byreferring to FIG. 1. In the CDMA, the wave that is transmitted on theup-link after being subjected to a spectrum spreading process in amobile terminal equipment UE, is subjected to a despreading process anda demodulation process by Rake combining in a base station apparatusNode-B so as to detect the desired wave.

Reception powers of the desired wave and the interference wave aremeasured after the despreading and the Rake combining, and a measuredvalue SIR_mes of a power relative value of the desired wave with respectto the interference wave is calculated. In order to maintain receptionquality, a reference SIR value SIR_tag is set in the base stationapparatus Node-B for each physical channel. A received SIR value SIR_mesobtained for each slot is compared with the reference SIR value SIR_tag,and a comparison result is reflected to power control information bits(TPC) that are transmitted to the mobile terminal equipment UE. Themobile terminal equipment UE uses the received power control informationbits (TPC) to vary an up-link transmission power level to the basestation apparatus Node-B.

The base station apparatus Node-B carries out an inner loop transmissionpower control with respect to the mobile terminal equipment EU. Forexample, in a case where the received SIR value SIR_mes in the basestation apparatus Node-B is smaller than the reference SIR valueSIR_tag, the base station apparatus Node-B uses the power controlinformation bits (TPC) and controls the transmission power of the mobileterminal equipment EU so as to increase. On the other hand, in a casewhere the received SIR value SIR_mes in the base station apparatusNode-B is larger than the reference SIR value SIR_tag, the base stationapparatus Node-B uses the power control information bits (TPC) andcontrols the transmission power of the mobile terminal equipment EU soas to decrease. The far-and-near problem between the base stationapparatus Node-B and the mobile terminal equipment UE is solved byperforming this inner loop transmission power control.

In the up-link power control, there is a demand to maintain thereception quality constant regardless of the propagation environment andthe moving velocity of the mobile terminal equipment UE. For thisreason, an outer loop transmission power control is employed to controlthe set value of the reference SIR value SIR_tag for maintaining thereception quality constant, from a radio network control apparatus RNCwith respect to the base station apparatus Node-B.

The radio network control apparatus RNC monitors the reception qualityof the up-link in the base station apparatus Node-B for everypredetermined period, and changes the set value of the reference SIRvalue SIR_tag using the information that is obtained as a result of themonitoring. In a case where the reception quality at the base stationapparatus Node-B has not reached a target quality, the radio networkcontrol apparatus RNC changes the set value of the reference SIR valueSIR_tag to a higher value. On the other hand, in a case where thereception quality at the base station apparatus Node-B has exceeded thetarget quality, the radio network control apparatus RNC changes the setvalue of the reference SIR value SIR_tag to a lower value. The radionetwork control apparatus RNC carries out the outer loop transmissionpower control in this manner.

Evaluation parameters that are used for the reception quality includeQuality Estimate (QE) and Cyclic Redundancy Check Indicator (CRCI).FIGS. 2A and 2B respectively are diagrams for explaining control of thereference SIR value SIR_tag when the QE and the RCI are used for thereception quality.

In the base station apparatus Node-B shown in FIG. 2A, a Bit Error Rate(BIR) is measured when carrying out a decoding (error correction)process with respect to the received signal from the mobile terminalequipment UE, and the QE is calculated from the measured BER. The valueQE_cal of the calculated QE is notified to the radio network controlapparatus RNC as the reception quality.

A target QE value QE_req is set in the radio network control apparatusRNC for each Radio Access Bearer RAB, and the radio network controlapparatus RNC compares the received QE value QE_cal and the target QEvalue QE_req. The radio network control apparatus RNC decreases thereference SIR value that is presently set if the received QE valueQE_cal is larger than the target QE value QE_req as a result of thecomparison, and increases the reference SIR value that is presently setif the received QE value QE_cal is smaller than the target QE valueQE_req as a result of the comparison. The reference SIR value that isset is updated in this manner.

The updated reference SIR value is notified to the base stationapparatus Node-B by a signal transmitting and receiving interface Iubbetween the radio network control apparatus RNC and the base stationapparatus Node-B. The base station apparatus Node-B sets the notifiedupdated reference SIR value as the reference SIR value SIR_tag.

In the base station apparatus Node-B shown in FIG. 2B, a reception erroris detected from Cyclic Redundancy Check (CRC) bits of a transport blockin units of Transport-Time Intervals (TTIs) when carrying out a decoding(error correction) process with respect to the received signal from themobile terminal equipment UE. A detection result of the reception erroris notified to the radio network control apparatus RNC as the CyclicRedundancy Check Indicator (CRCI).

The radio network control apparatus RNC updates the reference SIR valueby decreasing the reference SIR value if the notified CRCI indicates“normal reception (OK)” and increasing the reference SIR value if thenotified CRCI indicates “reception error (NG)”. The updated referenceSIR value is notified from the signal transmitting and receivinginterface Iub to the base station apparatus Node-B, and set as thereference SIR value SIR_tag for the base station apparatus Node-B.

One value is set for the up-link reference SIR value with respect toeach physical channel. When carrying out the outer loop control in acase where a plurality of transport channels (for example, audioservices, data services and the like) are mapped in one physical channel(for example, channels with identical frequency and spread code), theradio network control apparatus RNC monitors the reception quality of asingle transport channel of the plurality of transport channels, andreference SIR value SIR_tag is controlled by reflecting the informationthat is obtained by the monitoring of the reception quality. Thereference SIR value SIR_tag is increased or decreased depending onwhether or not the CRC or QE value for the measured transport channelthat has reached a target value.

An International Publication Number No. 98/47253 proposes a CDMAcommunication method that improves the utilization efficiency offrequency resources and the communication quality, by increasing thetransmission power in only a single a specified physical channel andtransmitting control information (pilot symbol and TPC symbol) inmulticode transmission.

A Japanese Laid-Open Patent Application No. 2001-217770 proposes atransmission power control that avoids mismatch of the outer loopcontrols before and after a handover connection.

A Japanese Laid-Open Patent Application No. 2001-285193 proposes anouter loop transmission power control that maintains a desiredcommunication quality in each of a plurality of channels even in a casewhere the transmission control information from the base station to themobile station is made up of only one bit.

A Japanese Laid-Open Patent Application No. 2003-18089 proposes a radiocommunication apparatus that maintains the reception quality to adesired quality regardless of a magnitude of the change in thepropagation environment when carrying out the outer loop transmissionpower control.

Next, a description will be given of the problems to be solved when theaudio is switched from a voiced state to a silent state.

FIG. 3 is a diagram showing coding and multiplexing schemes for theup-link when carrying out a multi-call transmission of packet channels(Interactive or Background/UL:32 kbps/Packet Switching Radio AccessBearer (RAB)) and audio channels (Conversational/Speech/UL:12.2kbps/Circuit Switching RAB) by Adaptive Multi-Rate (AMR) coding.

Three radio access bearers RAB#1, RAB#2 and RAB#3 are prescribed for theaudio transmission, and the number of kinds of transport block (TB)sizes is one (0 bit, 39 bits and 81 bits) for the radio access bearerRAB#1, one (103 bits) for the radio access bearer RAB#2, and one (60bits) for the radio access bearer RAB#3. The 0-bit transport block (TB)of the radio access bearer RAB#1 is transmitted even in a state (silentstate) where there are no data bits to be transmitted, and the CRC bitsare transmitted according to the transport block (TB) that istransmitted.

A single radio access bearer (RAB) is used when making a packettransmission, and the number of kinds of transport block (TB) sizes isone (336 bits). At each radio access bearer (RAB), the number oftransport blocks (TBs) transmitted during the TTI and the transportblock (TB) size are indicated by the value of a Transport FormatIndicator (TFI). Further, the value of a Transport Format CombinationIndicator (TFCI) is allocated with respect to a combination of theTransport Format Indicators (TFIs) of the radio access bearers (RABs)that are mapped when carrying out the multiplexing. Multiplexedinformation of a plurality of channels (for example, the numbers oftransport blocks (TBs), the transport block (TB) size and the like) in asingle physical channel will simply be referred to as “multiplexedinformation”.

When carrying out the multi-call transmission of the audio transmission(up-line, 12.2 kbps) and the packet transmission (up line, 32 kbps), theTransport Format Indicator (TFI) and the Transport Format CombinationIndicator (TFCI) are respectively allocated as shown in FIGS. 4A and 4B.As may be seen from FIG. 4B, there are nine Transport Format CombinationIndicators (TFCIs) C0 through C8.

The Transport Format Combination Indicators (TFCIs) are transmitted fromthe mobile terminal equipment UE to the base station apparatus Node-B ina state mapped on the physical channel. The base station apparatusNode-B detects the transport format from the received Transport FormatCombination Indicator (TFCI), so as to carry out the decoding processand a separation process to make a separation into the transport blocks(TBs) of each of the radio access bearers (RABs).

When the audio transport channels of the up-link are mapped on thephysical channel in the mobile terminal equipment UE, a convolutionencoder (constraint length 9, code rate 1/3) shown in FIG. 5A is used,but the coding efficiency changes depending on the number of data bits.A number of bits, Y, after the encoding can be described by thefollowing formula, where X denotes a number of data bits of the codeblock that is input to the convolution encoder, C denotes a number ofCRC bits that are added, T denotes a number of tail bits added to theend of the code block before the encoding. For example, T=8 bits and thevalue of all of the 8 bits are fixed to 0.Y=(X+C+T)×3

An encoding gain K_(X) in this case can be described by the followingformula.K _(X)={(X+C+T)×3}/(X+C)

In a silent state where X=0, an encoding gain K₀ can be described by thefollowing formula.K ₀={(C+T)×3}/C

In the radio access bearer RAB#1, C is prescribed to C=12 bits and amaximum value of X is X=81 bits. In this case, a difference of 1.86 dBoccurs between the encoding gain in the voiced state (K₈₁=3.26) and theencoding gain in the silent state (K₀=5.00). The encoding gain in thesilent state is larger, because the proportion of the tail bits withinthe total number of bits input to the encoder increases. Since theencoding gain differs between the voiced state and the silent state, theerror correction capability during the decoding process after the signalof the up-link is received by the base station apparatus Node-B becomesdifferent between the two states, to thereby affect the result of thequality measurements.

In the base station apparatus Node-B, a data sequence a(i) {i=1, 2, 3, .. . , Y} is input to a Viterbi decoder as shown in FIG. 5B, andconverted into a data sequence b(j) {j=1, 2, 3, . . . , Y/3} that hasbeen subjected to the error correction.

If the quality monitoring is made by the radio network control apparatusRNC using the QE value as the reception quality when carrying out theouter loop control, the obtained data sequence b(j) is again input tothe convolution encoder so as to obtain a data sequence of an outputa′(i) {i=1, 2, 3, . . . , Y}. From the data a(i) and a′(i), a Bit ErrorRate (BER) of the transport channels can be calculated from thefollowing formula, and the calculated BER value is used as the qualityinformation for the outer loop control.

${BER} = {\frac{1}{Y}{\sum\limits_{i = 1}^{Y}\left\lbrack {{a\;(i)} \oplus {a^{\prime}(i)}} \right\rbrack}}$

On the other hand, if the quality monitoring is made by the radionetwork control apparatus RNC using the CRCI judgement result as thereception quality when carrying out the outer loop control, the CRCIjudgement result may be affected depending on the magnitude of theencoding gain. When the outer loop control is carried out with respectto the audio transmission, the error correction capability during thedecoding process is improved in the silent state because the encodinggain in the silent state is large compared to that in the voiced state,and the CRCI judgement result becomes “normal reception (OK)” for mosttransport blocks (TBs). For this reason, in the radio network controlapparatus RNC, the quality in the silent state is estimated as beinghigh compared to that in the voiced state. Consequently, in order toobtain a transmission quality such that the transmission block errorrate (BLER) is approximately the same for the silent and voiced states,the reference SIR that is demanded has a smaller value for the silentstate.

Accordingly, when the outer loop transmission power control formonitoring the transmission quality is carried out for the audiotransmission radio access bearer RAB#1, with respect to the physicalchannel in which a plurality of radio access bearers (RABs) are mapped,which transmit packets of Internet-adapted contents service data, mailand the like, in addition to making audio transmission, a largedifference may be introduced between the qualities of the audiotransmission radio access bearer RAB#1 and another data transmissionradio access bearer (RAB) when the audio switches from the voiced stateto the silent state.

Normally, the quality difference between the radio access bearers (RABs)is adjusted by bit repetition or puncture during a rate matchingprocess. However, if the quality difference is considerably large, suchan adjustment is insufficient. When the outer loop control is carriedout with respect to the quality of the audio transmission radio accessbearer RAB#1 in such a situation, the transmission quality of the radioaccess bearer (RAB) other than the audio may deteriorate in some cases.

An example of this will now be described. When the audio transmissionaccess bearers (RABs) (up-line, 12.2 kbps) are mapped in the physicalchannel, it is assumed that the reference SIR value satisfying a targetvalue of the audio transmission quality decreases by a in the silentstate (TFI=0 for the radio access bearer RAB#1) compared to that in thevoiced state (TFI=2 for the radio access bearer RAB#1).

For the case where the audio transmission radio access bearer (up-line,12.2 kbps) and the packet transmission radio access bearer (up-line, 32kbps) are mapped in the same physical channel, FIG. 6A shows atransition of the reference SIR value with time when the outer looptransmission power control is not carried out, and FIG. 6B shows atransition of the reference SIR value with time when the outer looptransmission power control is carried out based on the qualitymonitoring of the audio transmission radio access bearer RAB#1.

When setting the physical channel in the base station apparatus Node-B,suppose that the reference SIR value is set to sir_12 by notification ofthe Node B Application Protocol (NBAP), the transport format indicator(TFI)=2 (voiced state) for the audio transmission radio access bearerRAB#1 and the transport format indicator (TFI)=2 for the packettransmission radio access bearer (RAB). In this state, a case will beconsidered where the audio is switched from the voiced state to thesilent state (TFI=0).

In the case where the outer loop transmission power control is notcarried out, the reference SIR value is fixed to sir_12 as shown in FIG.6A, regardless of the value of the transport format indicator (TFI) ofthe audio transmission radio access bearer (RAB). However, in the casewhere a difference is introduced in the qualities of the audiotransmission and the packet transmission due to the switching to thesilent state, and the outer loop control by the quality monitoring ofthe audio transmission radio access bearer RAB#1 is continued before andafter the switching, the reference SIR value decreases by a as shown inFIG. 6B. As a result, the audio quality is maintained constant, but thetransmission quality of the packet deteriorates when the switching tothe silent state is occurs due to the decrease of the reference SIRvalue.

Next, a description will be given of the problems to be solved whencarrying out an adding process to add a radio access bearer (RAB). Whencarrying out the outer loop control with respect to a specific physicalchannel, it is necessary to make the transmission according to thetarget quality even after the adding process is carried out to add theradio access bearer (RAB).

When setting the physical channel, suppose that the reference SIR valueis set to sir?1 in the base station apparatus Node-B by the NBAPnotification. In the case where no outer loop control is carried out,the reference SIR value is constant (sir_1). On the other hand, whencarrying out the outer loop control based on the quality monitoring ofwith respect to the radio access bearer RAB(1), a process is carried outto increase or decrease the reference SIR value based on the Iubnotification using sir_1 as a starting point. A change in the referenceSIR value with time will be considered, for the case where the radioaccess bearer RAB(2) is added to the physical channel to which the radioaccess bearer RAB(1) is mapped.

As shown in FIG. 7A, the radio network control apparatus RNC notifiesthe reference SIR value to the base station apparatus Node-B by the NBAPwhen adding the radio access bearer RAB(2), and updates the referenceSIR value by carrying out the outer loop transmission power control viathe interface Iub.

If the reference SIR value notified by the NBAP is sir_12 when addingthe radio access bearer RAB(2) and the outer loop transmission powercontrol is not carried out, the reference SIR value in the base stationapparatus Node-B becomes sir_12 and constant when adding the radioaccess bearer RAB(2), as shown in FIG. 7B.

When the radio access bearer RAB(2) is added when carrying out the outerloop transmission power control, the reference SIR value is once set tosir_12 in the base station apparatus Node-B by the NBAP notification, asshown in FIG. 7C. However, the process of increasing or decreasing thereference SIR value by the Iub notification from the radio networkcontrol apparatus RNC is carried out regardless of the setting by theNBAP notification, and the set value of the reference SIR value by theouter loop transmission power control is updated by inheriting the valuebefore the radio access bearer RAB(2) was added.

For this reason, as shown in FIG. 7C, the reference SIR value increasesto sir_12 immediately after the radio access bearer RAB(2) is added, butthereafter decreases to the original value due to the Iub notification.In order to satisfy the target quality of both the radio access bearersRAB(1) and RAB(2), it is necessary to increase the reference SIR valueto follow sir_12, but if the reference SIR value, sir_12, after addingthe radio access bearer RAB(2) is sufficiently large with respect to thereference SIR value, sir_1, before the radio access bearer RAB(2) wasadded, it requires a long time to increase the SIR value to a value thatsatisfies the target quality, and until this value that satisfies thetarget quality is reached, the transmission quality continues bedeteriorated.

Next, a description will be given of the problems to be solved whencarrying out a delete process to delete a radio access bearer (RAB). Ifthe outer loop control is carried out with respect to the physicalchannel to which a plurality of radio access bearers (RABs) are mappedand the delete process is carried out to delete a single radio accessbearer (RAB), it is necessary to carry out the transmission according tothe target quality even after the delete process is carried out. Forexample, when the radio access bearer RAB(2) is deleted in the physicalchannel to which the radio access bearer RAB(1) and the radio accessbearer RAB(2) are mapped, the reference SIR value changes with time asshown in FIG. 8B when the outer loop control is not carried out and asshown in FIG. 8C when the outer loop control is carried out.

When the physical channel to which the radio access bearer RAB(1) andthe radio access bearer RAB(2) are mapped is set, suppose that thereference SIR value is set to sir_12′ in the base station apparatusNode-B by the NBAP notification. The reference SIR value is sir_12′ whenthe outer loop transmission power control is not carried out. On theother hand, when the outer loop transmission power control is carriedout based on the quality monitoring with respect to the radio accessbearer RAB(1), the process of increasing or decreasing the reference SIRvalue is carried out based on the Iub notification using sir_12′ as astarting point.

The change in the reference SIR value with time will be considered for acase where the radio access bearer BAR(2) is deleted. As shown in FIG.13A, the radio network control apparatus RNC notifies the reference SIRvalue to the base station apparatus Node-B by the NBAP when deleting theradio access bearer RAB(2), and carries out the outer loop transmissionpower control via the interface Iub, to update the reference SIR value.

If it is assumed that the reference SIR value notified by the NBAP issir_1″ when deleting the radio access bearer RAB(2), the reference SIRvalue in the base station apparatus Node-B becomes sir_1′ and constantas shown in FIG. 8B when deleting the radio access bearer RAB(2).

If the radio access bearer RAB(2) is deleted when carrying out the outerloop control, the reference SIR value in the base station apparatus(Node-B) is once set to sir_1′ by the NBAP notification, as shown inFIG. 8C. However, the process of increasing or decreasing the referenceSIR value by the Iub notification is carried out regardless of thesetting by the NBAP notification. Consequently, the set value of thereference SIR value by the outer loop transmission power control isupdated by inheriting the value before the radio access bearer RAB(2)was deleted.

Therefore, as shown in FIG. 8C, the reference SIR value decreases tosir_1′ in the base station apparatus Node-B immediately after thedeletion of the radio access bearer RAB(2), but thereafter increases tothe original value by the Iub notification. As a result, the quality ofthe radio access bearer RAB(1) becomes excessively high with respect tothe target value.

It is thus necessary to decrease the reference SIR value to followsir_1′ in order to decrease the quality of the radio access bearerRAB(1) to the target value. However, if the reference SIR value, sir_1′,is sufficiently small with respect to the reference SIR value, sir_12′,before the radio access bearer RAB(2) was deleted, it requires a longtime to decrease the reference SIR value, and while the SIR value isbeing decreased, the quality becomes excessively high.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful transmission power control method and apparatus formobile communication system, in which the problems described above aresuppressed.

Another and more specific object of the present invention is to providea transmission power control method and apparatus for mobilecommunication system, which can carry out a transmission that alwaysenables a reception quality immediately conforming to a target qualityfor a set radio access bearer (RAB) to be obtained, even if a change ismade in the radio access bearers (RABs) or a considerable change is madein a number of data bits, such as a case where an audio switching ismade from a voiced state to a silent state and a case where a radioaccess bearer (RAB) is added or deleted, to thereby improve theperformance of an outer loop control of a multi-call setting, whencarrying out a transmission power control in a mobile communicationsystem.

Still another object of the present invention is to provide atransmission power control apparatus adapted to control a referencevalue for controlling a transmission power of a mobile terminalequipment based on a reception quality of a plurality of radio accessbearers at a base station apparatus, with respect to a physical channelto which the plurality of radio access bearers are mapped, when making aradio connection between the mobile terminal equipment and the basestation apparatus in a mobile communication system, the transmissionpower control apparatus comprising a judging part configured to judgewhether or not a radio access bearer that is a monitoring target of thereception quality is an audio transmission radio access bearer in asilent state, based on multiplexed information; and a switching partconfigured to switch the radio access bearer that is the monitoringtarget of the reception quality to a radio access bearer other than theaudio transmission radio access bearer in the silent state, if thejudging part judges that the radio access bearer that is the monitoringtarget of the reception quality is the audio transmission radio accessbearer in the silent state, wherein the reference value for controllingthe transmission power of the mobile terminal equipment is controlledbased on a reception quality of the radio access bearer other than theaudio transmission radio access bearer in the silent state. According tothe transmission power control apparatus of the present invention, it ispossible to prevent a sharp drop in the reference value when theswitching is made to the silent state, and to maintain the quality ofthe other radio access bearers. In addition, it is possible to carry outa transmission that always enables a reception quality immediatelyconforming to a target quality for a set radio access bearer (RAB) to beobtained, even if a change is made in the radio access bearers (RABs) ora considerable change is made in a number of data bits, such as a casewhere an audio switching is made from a voiced state to a silent stateand a case where a radio access bearer (RAB) is added or deleted, tothereby improve the performance of an outer loop control of a multi-callsetting, when carrying out a transmission power control in a mobilecommunication system.

A further object of the present invention is to provide a transmissionpower control apparatus adapted to control a referenceSignal-power-to-Interference-power Ratio (SIR) value for controlling atransmission power of a mobile terminal equipment based on a receptionquality of a plurality of radio access bearers at a base stationapparatus, with respect to a physical channel to which the plurality ofradio access bearers are mapped, when making a radio connection betweenthe mobile terminal equipment and the base station apparatus in a mobilecommunication system, the transmission power control apparatuscomprising a calculating part configured to calculate an increase ordecrease value of the reference SIR value for an inner loop transmissionpower control based on reception quality information; an updating partconfigured to update a reference value of the reference SIR value whenadding or deleting a radio access bearer; an adding part configured toadd the increase or decrease value to the reference value of thereference SIR value; and a notifying part configured to notify an addedvalue of the reference value and the increase or decrease value to thebase station apparatus as a set value of the reference SIR value,wherein a transmission power control is carried out by setting thereference SIR value based on an updated reference value when adding ordeleting the radio access bearer. According to the transmission powercontrol apparatus of the present invention, it is possible to preventthe quality from becoming deteriorated or to prevent an excessively highquality from being maintained, when the radio access bearer is added ordeleted. In addition, it is possible to carry out a transmission thatalways enables a reception quality immediately conforming to a targetquality for a set radio access bearer (RAB) to be obtained, even if achange is made in the radio access bearers (RABs) or a considerablechange is made in a number of data bits, such as a case where an audioswitching is made from a voiced state to a silent state and a case wherea radio access bearer (RAB) is added or deleted, to thereby improve theperformance of an outer loop control of a multi-call setting, whencarrying out a transmission power control in a mobile communicationsystem.

Another object of the present invention is to provide a transmissionpower control apparatus adapted to control a referenceSignal-power-to-Interference-power Ratio (SIR) value for controlling atransmission power of a mobile terminal equipment based on a receptionquality of a plurality of radio access bearers at a base stationapparatus, with respect to a physical channel to which the plurality ofradio access bearers are mapped, when making a radio connection betweenthe mobile terminal equipment and the base station apparatus in a mobilecommunication system, the transmission power control apparatuscomprising a calculating part configured to calculate an increase ordecrease value of the reference SIR value for an inner loop transmissionpower control based on reception quality information; an updating partconfigured to update a reference value of the reference SIR value whenadding or deleting a radio access bearer; and a notifying partconfigured to notify an updated reference value to the base stationapparatus, wherein the base station apparatus sets an added value of theincrease or decrease value and the reference value notified from a radionetwork control apparatus which controls the base station apparatus, asthe reference SIR value, and caries out a transmission power control bysetting the reference SIR value based on the updated reference valuewhen adding or deleting the radio access bearer. According to thetransmission power control apparatus of the present invention, it ispossible to prevent the quality from becoming deteriorated or to preventan excessively high quality from being maintained, when the radio accessbearer is added or deleted. In addition, it is possible to carry out atransmission that always enables a reception quality immediatelyconforming to a target quality for a set radio access bearer (RAB) to beobtained, even if a change is made in the radio access bearers (RABs) ora considerable change is made in a number of data bits, such as a casewhere an audio switching is made from a voiced state to a silent stateand a case where a radio access bearer (RAB) is added or deleted, tothereby improve the performance of an outer loop control of a multi-callsetting, when carrying out a transmission power control in a mobilecommunication system.

Still another object of the present invention is to provide atransmission power control method for controlling a reference value forcontrolling a transmission power of a mobile terminal equipment based ona reception quality of a plurality of radio access bearers at a basestation apparatus, with respect to a physical channel to which theplurality of radio access bearers are mapped, when making a radioconnection between the mobile terminal equipment and the base stationapparatus in a mobile communication system, the transmission powercontrol method comprising the steps of (a) judging whether or not aradio access bearer that is a monitoring target of the reception qualityis an audio transmission radio access bearer in a silent state, based onmultiplexed information; and (b) switching the radio access bearer thatis the monitoring target of the reception quality to a radio accessbearer other than the audio transmission radio access bearer in thesilent state, if the step (a) judges that the radio access bearer thatis the monitoring target of the reception quality is the audiotransmission radio access bearer in the silent state, wherein thereference value for controlling the transmission power of the mobileterminal equipment is controlled based on a reception quality of theradio access bearer other than the audio transmission radio accessbearer in the silent state. According to the transmission power controlmethod of the present invention, it is possible to prevent a sharp dropin the reference value when the switching is made to the silent state,and to maintain the quality of the other radio access bearers. Inaddition, it is possible to carry out a transmission that always enablesa reception quality immediately conforming to a target quality for a setradio access bearer (RAB) to be obtained, even if a change is made inthe radio access bearers (RABs) or a considerable change is made in anumber of data bits, such as a case where an audio switching is madefrom a voiced state to a silent state and a case where a radio accessbearer (RAB) is added or deleted, to thereby improve the performance ofan outer loop control of a multi-call setting, when carrying out atransmission power control in a mobile communication system.

A further object of the present invention is to provide a transmissionpower control method for controlling a referenceSignal-power-to-Interference-power Ratio (SIR) value for controlling atransmission power of a mobile terminal equipment based on a receptionquality of a plurality of radio access bearers at a base stationapparatus, with respect to a physical channel to which the plurality ofradio access bearers are mapped, when making a radio connection betweenthe mobile terminal equipment and the base station apparatus in a mobilecommunication system, the transmission power control method comprisingthe steps of (a) calculating an increase or decrease value of thereference SIR value for an inner loop transmission power control basedon reception quality information; (b) updating a reference value of thereference SIR value when adding or deleting a radio access bearer; (c)adding the increase or decrease value to the reference value of thereference SIR value; and (d) notifying an added value of the referencevalue and the increase or decrease value to the base station apparatusas a set value of the reference SIR value, wherein the steps (a) through(d) are carried out by a radio network control apparatus which controlsthe base station apparatus, and a transmission power control is carriedout by setting the reference SIR value based on an updated referencevalue when adding or deleting the radio access bearer. According to thetransmission power control method of the present invention, it ispossible to prevent the quality from becoming deteriorated or to preventan excessively high quality from being maintained, when the radio accessbearer is added or deleted. In addition, it is possible to carry out atransmission that always enables a reception quality immediatelyconforming to a target quality for a set radio access bearer (RAB) to beobtained, even if a change is made in the radio access bearers (RABs) ora considerable change is made in a number of data bits, such as a casewhere an audio switching is made from a voiced state to a silent stateand a case where a radio access bearer (RAB) is added or deleted, tothereby improve the performance of an outer loop control of a multi-callsetting, when carrying out a transmission power control in a mobilecommunication system.

Another object of the present invention is to provide a transmissionpower control method for controlling a referenceSignal-power-to-Interference-power Ratio (SIR) value for controlling atransmission power of a mobile terminal equipment based on a receptionquality of a plurality of radio access bearers at a base stationapparatus, with respect to a physical channel to which the plurality ofradio access bearers are mapped, when making a radio connection betweenthe mobile terminal equipment and the base station apparatus in a mobilecommunication system, the transmission power control method comprisingthe steps of (a) calculating an increase or decrease value of thereference SIR value for an inner loop transmission power control basedon reception quality information; (b) updating a reference value of thereference SIR value when adding or deleting a radio access bearer; and(c) notifying an updated reference value to the base station apparatus,wherein the steps (a) through (c) are carried out by a radio networkcontrol apparatus which controls the base station apparatus, and thebase station apparatus sets an added value of the increase or decreasevalue and the reference value notified from a radio network apparatus asthe reference SIR value, and caries out a transmission power control bysetting the reference SIR value based on the updated reference valuewhen adding or deleting the radio access bearer. According to thetransmission power control method of the present invention, it ispossible to prevent the quality from becoming deteriorated or to preventan excessively high quality from being maintained, when the radio accessbearer is added or deleted. In addition, it is possible to carry out atransmission that always enables a reception quality immediatelyconforming to a target quality for a set radio access bearer (RAB) to beobtained, even if a change is made in the radio access bearers (RABs) ora considerable change is made in a number of data bits, such as a casewhere an audio switching is made from a voiced state to a silent stateand a case where a radio access bearer (RAB) is added or deleted, tothereby improve the performance of an outer loop control of a multi-callsetting, when carrying out a transmission power control in a mobilecommunication system.

Other objects and further features of the present invention will beapparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for explaining an up-link transmission powercontrol;

FIGS. 2A and 2B respectively are diagrams for explaining an outer looptransmission power control using QE and RCI reception qualityparameters;

FIG. 3 is a diagram showing coding and multiplexing schemes for anup-link when carrying out a multi-call transmission of packet channelsand audio channels by AMR coding;

FIGS. 4A and 4B respectively are diagrams for explaining allocation ofTransport Format Indicator (TFI) and Transport Format CombinationIndicator (TFCI) when carrying out the multi-call transmission of packetchannels and audio channels;

FIGS. 5A and 5B respectively are diagrams for explaining a convolutionencoding in an up-link and calculation of a transport channel bit errorrate;

FIGS. 6A and 6B respectively are diagrams for explaining a change inreference SIR value with time when switching to a silent state;

FIGS. 7A through 7C respectively are diagrams for explaining a change inreference SIR value when adding a radio access bearer (RAB);

FIGS. 8A through 8C respectively are diagrams for explaining a change inreference SIR value when deleting a radio access bearer (RAB);

FIGS. 9A and 9B respectively are diagrams for explaining an operationand a change in SIR value with time when switching to a silent state ina first embodiment of a transmission power control apparatus accordingto the present invention;

FIGS. 10A and 10B respectively are diagrams for explaining an operationand a change in SIR value with time when adding a radio access bearer(RAB) in a second embodiment of the transmission power control apparatusaccording to the present invention;

FIGS. 11A and 11B respectively are diagrams for explaining an operationand a change in SIR value with time when adding a radio access bearer(RAB) in the second embodiment of the transmission power controlapparatus according to the present invention;

FIGS. 12A and 12B respectively are diagrams for explaining an operationand a change in SIR value with time when adding a radio access bearer(RAB) in a third embodiment of the transmission power control apparatusaccording to the present invention; and

FIGS. 13A and 13B respectively are diagrams for explaining an operationand a change in SIR value with time when deleting a radio access bearer(RAB) in the third embodiment of the transmission power controlapparatus according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 9A and 9B respectively are diagrams for explaining an operationand a change in SIR value with time when switching to a silent state ina first embodiment of a transmission power control apparatus accordingto the present invention. This first embodiment of the transmissionpower control apparatus employs a first embodiment of a transmissionpower control method according to the present invention.

In this first embodiment, a quality monitoring of a radio access bearer(RAB) in a radio network control apparatus RNC is carried out as followswhen carrying out an outer loop transmission power control, if an audiotransmission radio access bearer RAB#1 that employs an AdaptiveMulti-Rate (AMR) coding including no data bits is mapped in a physicalchannel.

When carrying out an outer loop transmission power control in thephysical channel to which a plurality of radio access bearers (RABs) aremapped in addition to the audio transmission radio access bearer RAB#1,the existence or non-existence of data is judged from a transport formatindicator (TFI) of the audio transmission radio access bearer RAB#1. Thevalue of the transport format indicator (TFI) of each radio accessbearer (RAB) is derived by a transport format combination indicator(TFCI) that is received by a base station apparatus Node-B and isnotified to the radio network control apparatus RNC.

In a case where the transport format indicator (TFI)=0 for the audiotransmission radio access bearer RAB#1, the audio transmission radioaccess bearer RAB#1 is excluded from a target of a quality monitoring ofthe outer loop transmission power control. If the value of the transportformat indicator (TFI) switches to 0 in a state where the qualitymonitoring is carried out with respect to the audio transmission radioaccess bearer RAB#1, the radio network control apparatus RNC continuesthe outer loop transmission power control by switching the target of thequality monitoring of the outer loop transmission power control toanother radio access bearer (RAB) having a transport format indicator(TFI) that is not 0.

In FIG. 9A, it is assumed for the sake of convenience that the outerloop transmission power control is carried out in the physical channelto which the audio transmission radio access bearer RAB#1 (up-line, 12.2kbps) and the packet transmission radio access bearer (RAB) (up-line, 32kbps) are mapped. Further, it is assumed that the set value of thereference SIR value by the NBAP notification when setting the physicalchannel is sir_12, the audio transmission radio access bearer RAB#1 hasa transport format indicator (TFI)=2 (voiced state), and the packettransmission radio access bearer (RAB) has a transport format indicator(TFI)=2.

The base station apparatus (Node-B) derives the transport formatindicator (TFI) of each radio access bearer (RAB) from the receivedtransport format combination indicator (TFCI) and notifies the transportformat indicator (TFI) to the radio network control apparatus RNC. Theradio network control apparatus RNC carries out the outer looptransmission power control with the target of the quality monitoringbeing the voiced audio transmission radio access bearer RAB#1, asindicated in the top portion of FIG. 9A. The lower portion of FIG. 9Ashows the operation when the audio switches from the voiced state to thesilent state where the transport format indicator (TFI)=0, and FIG. 9Bshows a change in the reference SIR value with time.

When the switching to the silent state is made, the radio networkcontrol apparatus RNC recognizes that the transport format indicator(TFI) of the audio transmission radio access bearer RAB#1 has become 0and excludes the audio transmission radio access bearer RAB#1 from thetarget of the quality monitoring. In addition, the radio network controlapparatus RNC continues the outer loop transmission power control byswitching the target of the quality monitoring to the packettransmission radio access bearer (RAB) having the transport format index(TFI) that is 2, and notifies the reference SIR value to the basestation apparatus Node-B. Hence, it is possible to prevent a sharp dropin the reference SIR value when the audio is switched to the silentstate, to thereby maintain the quality of the packet transmission.

Next, a description will be given of a second embodiment of thetransmission power control apparatus according to the present invention.FIGS. 10A and 10B respectively are diagrams for explaining an operationand a change in SIR value with time when adding a radio access bearer(RAB) in the second embodiment of the transmission power controlapparatus according to the present invention. FIGS. 11A and 11Brespectively are diagrams for explaining an operation and a change inSIR value with time when adding a radio access bearer (RAB) in thesecond embodiment of the transmission power control apparatus accordingto the present invention. This second embodiment of the transmissionpower control apparatus employs a second embodiment of the transmissionpower control method according to the present invention.

In this second embodiment, when carrying out the outer loop transmissionpower control, the setting of the reference SIR value is made as followsif the radio access bearer (RAB) is added or deleted. When a specificphysical channel is set, it is assumed for the sake of convenience thatthe reference SIR value that is set by the NBAP notification isSIR_before, and the outer loop transmission power control is carried outin this state.

In the radio network control apparatus RNC, an increase or decrease(change) value ΔSIR of the reference SIR value is derived based onup-link reception quality information that is obtained from the basestation apparatus Node-B. The increase or decrease value ΔSIR changesfor every specific period of the outer loop transmission power control.In the radio network control apparatus RNC, SIR_before is added as areference value every time the increase or decrease value ΔSIR isupdated, and an added value (SIR_before+ΔSIR) that is obtained isnotified to the base station apparatus Node-B by the Iub. In the basestation apparatus Node-B, the added value (SIR_before+ΔSIR) is set asthe reference SIR value so as to update the reference SIR value.

If an adding or detecting process is carried out to add or delete theradio access bearer (RAB) in a state where this outer loop transmissionpower control is continued, the reference SIR value notified by the NBAPis set to SIR_after. In the radio network control apparatus RNC, thereference value of the reference SIR value is changed from SIR_before toSIR_after, and an added value (SIR_after+ΔSIR) of the reference valueand the ΔSIR value is notified to the base station apparatus Node-B bythe Iub every time the ΔSIR value is updated, so as to set and updatethe reference SIR value. The reference value of the reference SIR valueis notified to the base station apparatus (Node-B) by the NBAP, and issuccessively updated every time the adding or deleting process iscarried out with respect to the radio access bearer (RAB).

FIG. 10A shows the operation of the outer loop transmission powercontrol before and after the adding process with respect to the radioaccess bearer (RAB) in this second embodiment, and FIG. 10B shows achange in the reference SIR value with time. It is assumed for the sakeof convenience that the outer loop transmission power control is carriedout in the physical channel to which the radio access bearer RAB(1) ismapped. When setting the physical channel, the reference SIR value isset to sir_1 by the NBAP notification, and an increase or decrease(change) value Δsir of the reference SIR value is calculated by theouter loop transmission power control that is carried out with the radioaccess bearer RAB(1) as the target of the quality monitoring.

When the value of the increase or decrease value Δsir is updated, theradio network control apparatus RNC notifies an added value (sir_1+Δsir)of the reference value sir_1 and the increase or decrease value Δsir tothe base station apparatus Node-B by the Iub. The base station apparatusNode-B updates the reference SIR value to the added value (sir_1+Δsir).

When the radio access bearer RAB(2) is added in this state, the radionetwork control apparatus RNC changes the reference value of thereference SIR value to sir_12 and continues the outer loop transmissionpower control. In addition, the radio network control apparatus RNCnotifies the calculated reference SIR value (sir_12+Δsir) to the basestation apparatus Node-B, so as to set and update the reference SIRvalue in the base station apparatus Node-B. sir_12 is the reference SIRvalue that is set by the NBAP when carrying out the adding process ofthe radio access bearer RAB(2), and sir_1<sir_12.

By setting and updating the reference SIR value in this manner, itbecomes possible to carry out the outer loop transmission power controlby setting the reference SIR value adaptively to the quality monitoringafter the change in the radio access bearer (RAB) immediately after theadding process of the radio access bearer (RAB), and to preventdeterioration of the quality, as shown in FIG. 11B, even if thereference value sir_12 of the reference SIR value after adding the radioaccess bearer (RAB) is sufficiently large compared to the referencevalue sir_1 of the reference SIR value before adding the radio accessbearer (RAB).

FIG. 11A shows the operation of the outer loop transmission powercontrol before and after the deleting process with respect to the radioaccess bearer (RAB) in this second embodiment, and FIG. 11B shows achange in the reference SIR value with time. It is assumed for the sakeof convenience that the outer loop transmission power control is carriedout in the physical channel to which the radio access bearers RAB(1) andRAB(2) are mapped. When setting the physical channel, the reference SIRvalue is set to sir_12′ by the NBAP notification, and an increase ordecrease (change) value Δsir of the reference SIR value is calculated bythe outer loop transmission power control that is carried out with theradio access bearer RAB(1) as the target of the quality monitoring.

When the value of the increase or decrease value Δsir is updated, theradio network control apparatus RNC notifies an added value(sir_12′+Δsir) of the reference value sir_12′ and the increase ordecrease value Δsir to the base station apparatus Node-B by the Iub. Thebase station apparatus Node-B updates the reference SIR value to theadded value (sir_12′+Δsir).

When the radio access bearer RAB(2) is deleted in this state, the radionetwork control apparatus RNC changes the reference value of thereference SIR value to sir_1′ and continues the outer loop transmissionpower control. In addition, the radio network control apparatus RNCnotifies the calculated reference SIR value (sir_1′+Δsir) to the basestation apparatus Node-B, so as to set and update the reference SIRvalue in the base station apparatus Node-B. sir_1′ is the reference SIRvalue that is set by the NBAP when carrying out the deleting process ofthe radio access bearer RAB(2), and sir_12′<sir_1′.

By setting and updating the reference SIR value in this manner, itbecomes possible to carry out the outer loop transmission power controlby setting the reference SIR value adaptively to the quality monitoringafter the change in the radio access bearer (RAB) immediately after thedeleting process of the radio access bearer (RAB), and to prevent anexcessively high quality from being maintained, even if the referencevalue sir_1′ of the reference SIR value after deleting the radio accessbearer (RAB) is sufficiently small compared to the reference valuesir_12′ of the reference SIR value before deleting the radio accessbearer (RAB).

Next, a description will be given of a third embodiment of thetransmission power control apparatus according to the present invention.FIGS. 12A and 12B respectively are diagrams for explaining an operationand a change in SIR value with time when adding a radio access bearer(RAB) in the third embodiment of the transmission power controlapparatus according to the present invention. FIGS. 13A and 13Brespectively are diagrams for explaining an operation and a change inSIR value with time when deleting a radio access bearer (RAB) in thethird embodiment of the transmission power control apparatus accordingto the present invention. This third embodiment of the transmissionpower control apparatus employs a third embodiment of the transmissionpower control method according to the present invention.

In this third embodiment, when carrying out the outer loop transmissionpower control, the setting of the reference SIR value is made as followsif the radio access bearer (RAB) is added or deleted. When a specificphysical channel is set, it is assumed for the sake of convenience thatthe reference SIR value that is set by the NBAP notification isSIR_before, and the outer loop transmission power control is carried outin this state.

In the radio network control apparatus RNC, an increase or decrease(change) value ΔSIR of the reference SIR value is derived based onup-link reception quality information that is obtained from the basestation apparatus Node-B. The increase or decrease value ΔSIR changesfor every specific period of the outer loop transmission power control.The radio network control apparatus RNC notifies the increase ordecrease value ΔSIR to the base station apparatus Node-B by the Iubevery time the increase or decrease value ΔSIR is updated.

In the base station apparatus Node-B, SIR_before is added as a referencevalue to the increase or decrease value ΔSIR that is received from theradio network control apparatus RNC, and sets the reference SIR value tothe added value (SIR_before+ΔSIR) so as to update the reference SIRvalue. If an adding or detecting process is carried out to add or deletethe radio access bearer (RAB) in a state where this outer looptransmission power control is continued, it is assumed for the sake ofconvenience that the reference SIR value that notified by the NBAP isSIR_after.

In the base station apparatus Node-B, the reference value of thereference SIR value is changed from SIR_before to SIR_after, and everytime the increase or decrease value ΔSIR is notified fro the radionetwork control apparatus RNC to the base station Node-B by the Iub, anadded value (SIR_after+ΔSIR) of the reference value and the ΔSIR valueis calculated, so as to set and update the reference SIR value. Thereference value of the reference SIR value is successively updated everytime the adding or deleting process is carried out with respect to theradio access bearer (RAB) by the NBAP.

FIG. 12A shows the operation of the outer loop transmission powercontrol before and after the adding process with respect to the radioaccess bearer (RAB) in this third embodiment, and FIG. 12B shows achange in the reference SIR value with time. It is assumed for the sakeof convenience that the outer loop transmission power control is carriedout in the physical channel to which the radio access bearer RAB(1) ismapped. When setting the physical channel, the reference SIR value isset to sir_1 by the NBAP notification, and an increase or decrease(change) value Δsir of the reference SIR value is calculated by theouter loop transmission power control that is carried out with the radioaccess bearer RAB(1) as the target of the quality monitoring.

When the value of the increase or decrease value Δsir is updated, theradio network control apparatus RNC notifies the increase or decreasevalue Δsir to the base station apparatus Node-B by the Iub. The basestation apparatus Node-B updates and sets the reference SIR value to anadded value (sir_1+Δsir) of the reference value sir_1 of the referenceSIR value and the increase or decrease value Δsir, by adding thereference value sir_1 of the reference SIR value to the increase ordecrease value Δsir that is received from the radio network controlapparatus RNC.

When the radio access bearer RAB(2) is added in this state, the basestation apparatus Node-B changes the reference value of the referenceSIR value to sir_12, and adds the increase or decrease value Δsirnotified from the radio network control apparatus RNC by the outer looptransmission power control, so as to set and update the reference SIRvalue to the obtained value (sir_12+Δsir). sir_12 is the reference SIRvalue that is set by the NBAP when carrying out the adding process ofthe radio access bearer RAB(2), and sir_1<sir_12.

By setting and updating the reference SIR value in this manner, itbecomes possible to carry out the outer loop transmission power controlby setting the reference SIR value adaptively to the quality monitoringafter the change in the radio access bearer (RAB) immediately after theadding process of the radio access bearer (RAB), and to preventdeterioration of the quality, as shown in FIG. 12B, even if thereference value sir_12 of the reference SIR value after adding the radioaccess bearer (RAB) is sufficiently large compared to the referencevalue sir_1 of the reference SIR value before adding the radio accessbearer (RAB).

FIG. 13A shows the operation of the outer loop transmission powercontrol before and after the deleting process with respect to the radioaccess bearer (RAB) in this third embodiment, and FIG. 13B shows achange in the reference SIR value with time. It is assumed for the sakeof convenience that the outer loop transmission power control is carriedout in the physical channel to which the radio access bearers RAB(1) andRAB(2) are mapped. When setting the physical channel, the reference SIRvalue is set to sir_12′ by the NBAP notification, and an increase ordecrease (change) value Δsir of the reference SIR value is calculated bythe outer loop transmission power control that is carried out with theradio access bearer RAB(1) as the target of the quality monitoring.

When the value of the increase or decrease value Δsir is updated, theradio network control apparatus RNC notifies the increase or decreasevalue Δsir to the base station apparatus Node-B by the Iub. The basestation apparatus Node-B adds a reference value sir_12′ of the referenceSIR value to the increase or decrease value Δsir that is received fromthe radio network control apparatus RNC, and sets and updates thereference SIR value to the added value (sir_12′+Δsir).

When the radio access bearer RAB(2) is deleted in this state, the basestation apparatus Node-B changes the reference value of the referenceSIR value to sir_1′ and adds the increase or decrease value Δsir that isnotified from the radio network control apparatus RNC by the outer looptransmission power control, to set and update the reference SIR value tothe added value (sir_1′+Δsir). sir_1′ is the reference SIR value that isset by the NBAP when carrying out the deleting process of the radioaccess bearer RAB(2), and sir_12′<sir_1′.

By setting and updating the reference SIR value in this manner, itbecomes possible to carry out the outer loop transmission power controlby setting the reference SIR value adaptively to the quality monitoringafter the change in the radio access bearer (RAB) immediately after thedeleting process of the radio access bearer (RAB), and to prevent anexcessively high quality from being maintained, even if the referencevalue sir_1′ of the reference SIR value after deleting the radio accessbearer (RAB) is sufficiently small compared to the reference valuesir_12′ of the reference SIR value before deleting the radio accessbearer (RAB).

Further, the present invention is not limited to these embodiments, butvarious variations and modifications may be made without departing fromthe scope of the present invention.

1. A transmission power control apparatus adapted to control a referencevalue for controlling a transmission power of a mobile terminalequipment based on a reception quality of a plurality of radio accessbearers at a base station apparatus, with respect to a physical channelto which the plurality of radio access bearers are mapped, when making aradio connection between the mobile terminal equipment and the basestation apparatus in a mobile communication system, said transmissionpower control apparatus comprising: a judging part configured to judgewhether or not a radio access bearer that is a monitoring target of thereception quality is an audio transmission radio access bearer in asilent state, based on multiplexed information; and a switching partconfigured to switch the radio access bearer that is the monitoringtarget of the reception quality to a radio access bearer other than theaudio transmission radio access bearer in the silent state, if saidjudging part judges that the radio access bearer that is the monitoringtarget of the reception quality is the audio transmission radio accessbearer in the silent state, wherein the reference value for controllingthe transmission power of the mobile terminal equipment is controlledbased on a reception quality of the radio access bearer other than theaudio transmission radio access bearer in the silent state.
 2. Atransmission power control method for controlling a reference value forcontrolling a transmission power of a mobile terminal equipment based ona reception quality of a plurality of radio access bearers at a basestation apparatus, with respect to a physical channel to which theplurality of radio access bearers are mapped, when making a radioconnection between the mobile terminal equipment and the base stationapparatus in a mobile communication system, said transmission powercontrol method comprising the steps of: (a) judging whether or not aradio access bearer that is a monitoring target of the reception qualityis an audio transmission radio access bearer in a silent state, based onmultiplexed information; and (b) switching the radio access bearer thatis the monitoring target of the reception quality to a radio accessbearer other than the audio transmission radio access bearer in thesilent state, if said step (a) judges that the radio access bearer thatis the monitoring target of the reception quality is the audiotransmission radio access bearer in the silent state, wherein thereference value for controlling the transmission power of the mobileterminal equipment is controlled based on a reception quality of theradio access bearer other than the audio transmission radio accessbearer in the silent state.